Grape seed procyanidin extract (GSE), and milk thistle silymarin extract (MTE) are widely used health food supplements to promote cardiovascular (CV) and hepatobiliary health, respectively. Both GSE and MTE contain high levels of polyphenols that are structurally distinct with strong antioxidant properties, and each agent has been shown to exert antineoplastic effects against lung cancer. Preliminary data using combinations of GSE and MTE shows exciting, unequivocal synergistic anticancer effects against lung pre- and cancer cells in vitro. We therefore hypothesize that oral administration of combinations of leucoselect phytosome (LP), a standardized GSE, and siliphos, a standardized MTE, both complexed with soy phospholipids into phytosomes to enhance bioavailability, will synergistically inhibit lung cancer growth, invasion, and induce apoptosis in various human lung cancer xenograft models, via favorable modulations of mechanisms associated with lung tumorigenesis/promotion. To test these hypotheses, we will determine their pharmacokinetics (PK) and pharmacodynamics (PD). We will also determine the utility of biospecimens, such as snap, fresh frozen lung tissue homogenates, as surrogate model systems to monitor the bioavailability and bioactivity of oral administration of these agents to the target organ. Furthermore, the mechanistic effects of the combinations will be assessed systematically with cancer relevant, pathway specific gene expressions and microRNA (miRNA) real time PCR arrays, and correlated to functional significance. Three specific aims are proposed: Aim 1: To determine the maximum tolerated dose (MTD), PK/PD, and anti-cancer effects of LP with siliphos in murine models. A dose range finding study will be conducted in nude mice given varying dose combinations via oral gavage to establish MTD. Blood and lung samples will be obtained to determine PK of GSE, MTE and metabolites as surrogate markers of bioavailability of GSE and MTE. Aim 1.1. To determine the bioactivity of oral LP and siliphos using a novel co-culture system of frozen mouse lung homogenates with human lung neoplastic cells. Bioactivity in the lungs will be assessed by co-culturing lung tissue homogenates from control (water) vs. drug treated mice with human lung cancer and precancerous cell lines. The effects of varying dose combinations on proliferation and apoptosis in co-cultured cells will be correlated to GSE, MTE and metabolites levels. Aim 2: To determine the anti-cancer effects of combinations of LP and siliphos on various types of human lung cancer xenograft mouse models. Based on MTD findings, varying dose combinations will be given via oral gavage to mice bearing a variety of human lung tumor xenografts for up to 8 weeks with serial collections of plasma, lung tissues and tumor xenografts from each treatment group. The anticancer effects will be determined by tumor growth delay or time to reach maximum tumor volume, as well as proliferation (Ki- 67) and apoptotic (cleaved caspase 3) indices, and correlated to GSE & MTE levels in various biospecimens, to define physiologically relevant levels in reference to bioactivity. Aim 3: To identify, characterize and correlate the molecular mechanisms of GSE with MTE against lung cancer. The mechanistic effects will be assessed and correlated systematically and comprehensively, by comparing the bioactivity pre- or post treatment, in various sample types, as measured by modulations of: 1) eicosanoid signaling pathways; 2) additional markers of inflammations and anti-tumor immunity, interleukin (IL)-6, IL-10, IL-12; 3) mir-19a, -19b and 106b levels; 4) cancer relevant, pathway specific gene expression profiles; 5) epigenetic profiles assessed by miRNA expression array, and 6) common biomarkers of cancerization such as PTEN, IGF2R, P53, p27, p21, p16, FHIT, and BIRC5. IMPACT: Findings from the study will provide important insights into the feasibility and mechanistic effects of combinations of GSE and MTE against lung cancer, and pave the way for clinical trials in the near future, with enormous potential in advancing the treatment and prevention of lung cancer.